The present invention relates generally to the field of heat exchangers and methods and apparatus for manufacturing heat exchangers. More particularly, the invention relates to an apparatus for brazing a heat exchanger, in particular a flat-tube condenser. According to another aspect, the invention relates to a method for brazing a heat exchanger, and in accordance with yet another aspect, the invention also relates to a heat exchanger.
Heat exchangers, in particular, flat-tube condensers, are used for motor vehicle air-conditioning systems. Heat exchangers of this type are predominantly produced from aluminum alloys and are made by brazing in a brazing furnace. Such flat-tube condensers—as known, for example, from DE-A 42 38 853—comprise a heat transfer network or block, which is built up from a large number of flat tubes and corrugated fins arranged between the tubes, and manifold or header tubes, into which the flat tubes open. The production of a flat-tube condenser built up in this way is carried out in that, first of all, the parts for the block, that is to say the flat tubes and corrugated fins, are joined mechanically (they are “blocked”) in a corresponding machine, which is known as the block producer. In order to achieve satisfactory brazing of the corrugated fins to the flat tubes, the assembled block is clamped transversely with respect to the longitudinal direction of the tubes, in order that all the corrugations of the corrugated fins rest uniformly on the flat tubes. In this clamped or compressed state, the block is moved into the brazing furnace, while being held in a brazing apparatus, and is brazed there. When the brazing temperature is reached, the brazing material located on the fins and/or tubes is melted and the entire block “is set.” Then, following brazing, the heat exchanger can be removed from the brazing apparatus after it has cooled to at least some degree.